Various conventional liquid crystal display panels for use in, for example, laptop computers have a backlight using a plurality of cold cathode fluorescent lamps (hereinafter referred to as CCFLs).
An inverter driving circuit is normally used to light such CCFLs. The inverter driving circuit is classified into an external-excited inverter driving circuit in which an inductor and a capacitor on a secondary side of a transformer form a resonance circuit and in which a dedicated IC is used to drive the lamps in the vicinity of a resonance point of the resonance circuit and a self-excited inverter driving circuit in which a Royer circuit or the like is used to form a voltage resonance circuit on a primary side of the transformer. Various circuits of the respective types have been proposed (see, for example, Patent Documents 1 and 2).    Patent Document 1: Japanese Unexamined Patent Publication No. 2004-350444    Patent Document 2: Japanese Unexamined Patent Publication No. 2002-175891